Revert of Added first layer of the echo canceller 3 functionality

webrtc/modules/audio_processing/aec3/cascaded_biquad_filter.cc

Index: webrtc/modules/audio_processing/aec3/cascaded_biquad_filter.cc
diff --git a/webrtc/modules/audio_processing/aec3/cascaded_biquad_filter.cc b/webrtc/modules/audio_processing/aec3/cascaded_biquad_filter.cc
deleted file mode 100644
index da50c7d1932d95db944ff0545a86d069a8f64202..0000000000000000000000000000000000000000
--- a/webrtc/modules/audio_processing/aec3/cascaded_biquad_filter.cc
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-#include "webrtc/modules/audio_processing/aec3/cascaded_biquad_filter.h"
-
-#include "webrtc/base/checks.h"
-
-namespace webrtc {
-
-CascadedBiQuadFilter::CascadedBiQuadFilter(
-    const CascadedBiQuadFilter::BiQuadCoefficients& coefficients,
-    size_t num_biquads)
-    : biquad_states_(num_biquads), coefficients_(coefficients) {}
-
-CascadedBiQuadFilter::~CascadedBiQuadFilter() = default;
-
-void CascadedBiQuadFilter::Process(rtc::ArrayView<const float> x,
-                                   rtc::ArrayView<float> y) {
-  ApplyBiQuad(x, y, &biquad_states_[0]);
-  for (size_t k = 1; k < biquad_states_.size(); ++k) {
-    ApplyBiQuad(y, y, &biquad_states_[k]);
-  }
-}
-
-void CascadedBiQuadFilter::Process(rtc::ArrayView<float> y) {
-  for (auto& biquad : biquad_states_) {
-    ApplyBiQuad(y, y, &biquad);
-  }
-}
-
-void CascadedBiQuadFilter::ApplyBiQuad(
-    rtc::ArrayView<const float> x,
-    rtc::ArrayView<float> y,
-    CascadedBiQuadFilter::BiQuadState* biquad_state) {
-  RTC_DCHECK_EQ(x.size(), y.size());
-  RTC_DCHECK(biquad_state);
-  const auto c_b = coefficients_.b;
-  const auto c_a = coefficients_.a;
-  auto m_x = biquad_state->x;
-  auto m_y = biquad_state->y;
-  for (size_t k = 0; k < x.size(); ++k) {
-    const float tmp = x[k];
-    y[k] = c_b[0] * tmp + c_b[1] * m_x[0] + c_b[2] * m_x[1] - c_a[0] * m_y[0] -
-           c_a[1] * m_y[1];
-    m_x[1] = m_x[0];
-    m_x[0] = tmp;
-    m_y[1] = m_y[0];
-    m_y[0] = y[k];
-  }
-}
-
-}  // namespace webrtc